1. Field of Invention
The present invention relates to a method and a system for controlling braking of a vehicle, and more particularly, to a method and a system for controlling braking of a vehicle, which provide stable braking force by compensating for master cylinder hydraulic pressure in a case in which a required negative pressure is not formed at the time of braking.
2. Description of Related Art
A brake device is provided in a vehicle to decelerate or stop the vehicle being in a state of traveling as necessary.
The brake device generates braking force by converting kinetic energy of the vehicle being in a state of traveling into thermal energy by using frictional force and emitting thermal energy into the atmosphere.
Hydraulic pressure is generated in a master cylinder by an operation of a brake pedal, and the hydraulic pressure is transmitted to a wheel brake such that the vehicle is decelerated or stopped.
Engine negative pressure is generated in an intake stroke, and performance of negative pressure is determined by various factors such as a mechanical frictional load of an engine, efficiency of a transmission, and the like.
In a case in which the engine negative pressure is insufficient, because boosting force by a booster is small, a driver feels that a brake pedal is stiff and the braking force is insufficient at the moment when a magnitude of pressure in a brake hydraulic pressure line and a magnitude of tread force on the brake pedal are identical to each other.
In addition, in a case in which negative pressure, which is required to brake, is not sufficient, operational feeling for the brake pedal deteriorates, and because the braking force is insufficient, a problem of traveling safety may occur.
Accordingly, in order to achieve an improvement on engine negative pressure, a technology is being provided which secures stable brake performance with a method of compensating for the engine negative pressure by additionally including an electric vacuum pump.
However, as the high priced vacuum pump is further added, there are problems in that price competitiveness deteriorates because a manufacturing cost is increased, productivity deteriorates because a layout design and an assembly process are complicated, and fuel efficiency and engine output torque deteriorate because a weight is increased, and a load to drive the vacuum pump is shared.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.